The paradox is that in the decades since Cuba was first embargoed in 1960, the intended target of sanctions - whether it be Cuban President Fidel Castro, Iraqi leader Saddam Hussein, or Serbia's President Slobodan Milosevic - has been able to turn sanctions to political advantage, while neatly handing off the burden to local populations.

The tangle of US sanctions today affect more than half the world's population. But the severity of Iraq's case has for the first time built up a diplomatic head of steam against sanctions for what the US sees as global wrongdoing.

The growing chorus of protest was capped by last Thursday's departure from Baghdad of Hans Von Sponeck, UN humanitarian chief, for Iraq. He resigned rather than preside over the further destruction of Iraq's social fabric.

"Let's face it: Iraq is one of the few countries on our globe which is regressing," said the 32-year UN veteran, in his first interview since leaving Iraq. "I have no doubt that history will say that Iraq was forced to become the guinea pig for the experimentation of a sanction methodology that ultimately failed. We have to find a new approach."

Sanctions may be the modern equivalent of the military siege, in which armies throughout history - from the Romans surrounding the Masada (an ancient Jewish fortress in Israel), to the Germans and Finnish blockading Leningrad in World War II - sought to compel capitulation by destroying the will to resist.

Roots of the American policy reach back to President Woodrow Wilson, who said in 1919 that "a nation boycotted is a nation that is in sight of surrender."

That maxim seems to have been taken to heart by President Clinton, for whom sanctions have all but replaced diplomacy. He has called the US "sanctions happy," and long with Congress, he has been responsible for imposing more than half of the 125 or so cases of sanctions ever imposed by the US.

But such overuse "devalues the tool" and the "moral, disapproval value tends to be lost," says Gary Hufbauer, a sanctions expert and senior fellow at the Institute for International Economics in Washington. Economists estimate that sanctions cost Americans some $20 billion a year in lost export sales, and up to 200,000 jobs.

The lessons of nearly 10 years of sanctions on Iraq are causing analysts to reexamine their assumptions about what few sanctions - out of the 176 recorded cases this century - have caused their targets to change course, and why so many have failed.

"We've done a lot of re-evaluating," Mr. Hufbauer says. "The unfortunate truth is that when you have a truly retrograde regime, and you are seeking a major goal like its overthrow, the record is close to zero."

Sanctions have been applied from North Korea to Canada, and both India and Pakistan were slapped with sanctions - mandatory under US law - when they tested nuclear devices in 1998. Those sanctions hurt US farm exports badly, renewing interest in Congress for reform that would require assessing domestic impact before imposing any sanction.

Despite those cases, Iraq stands out. "Iraq in our times, is like the Italian-Abyssinia case was to the League of Nations. That was the defining sanction, and it did as much as anything to destroy the League," says Hufbauer. "The Iraq case is not going to destroy the UN, but it is certainly causing a lot of rethinking. The lasting impact is that it will be much harder to put these kind of sanctions on any country."

A similar analysis has been put forward by a Brittish parliamentary committee, that found that the Iraq example showed it would be "difficult" to justify imposing similar sanctions on any nation in the future, because they cause "impoverishment" and "only further concentrate power in the hands of the ruling elite."

Comprehensive UN sanctions were slapped on Iraq in August 1990, just days after Iraqi forces invaded Kuwait - and remain the pillar of US policy toward Iraq. Since 1996, Iraq has been permitted to sell oil to buy humanitarian goods, but US officials have blocked scores of contracts, anxious that "dual use" items might be used to reinvigorate Iraq's nuclear-, chemical-, and biological-weapons programs.

The US has come under intense pressure from friend and foe alike the past two weeks in the UN Security Council. In a rare moment of criticism, UN head Kofi Annan noted that sanctions had created a "serious moral dilemma" for the UN, and that the US and Britain had blocked more than $1.5 billion worth of humanitarian contracts for Iraq - for items from breeding bulls to ambulances.

"The UN has been on the side of the vulnerable and the weak, and has always sought to relieve suffering. Yet, here we are accused of causing suffering," Mr. Annan said.

Senior US officials have said repeatedly that the Iraqi people are not the targets of sanctions, and have agreed to release at least 70 of the applications for humanitarian goods that it had put on hold. "There is no question that sanctions fatigue is becoming a major problem," says Anthony Cordesman, a leading Mideast security expert at the Center for Strategic and International Studies in Washington. "There is immense hardship in Iraq.... You certainly have a nation that is falling apart in every way - except in sustaining a dictatorship."

"The idea that we are engaged in a constant battle for perceptions, and that the key perception is the welfare of the Iraqi people, seems to be absolutely beyond the comprehension of the State Department," Mr. Cordesman says. "If you look back on [Secretary of State] Madeleine Albright's tenure, this will probably be recognized as one of the greatest single failures for which she has to be held responsible."

Oil-rich Iraq was once one of the wealthiest nations in the Mideast. But a decade of war in the 1980s, the 1991 Gulf War, and then sanctions have all resulted in a spike in extreme malnutrition rates. Child deaths now number in the hundreds of thousands, and there has been an almost total breakdown of health and other basic services, according to UN statistics.

Mr. Von Sponeck points out that the Iraqi leadership has spent the $400 million a year from illicit smuggling of oil on everything from new palaces to whiskey, and he is disappointed at how little it spends from legal UN oil money on education.

"I don't say that everything that impinges on Iraq is due to sanctions. Rubbish," he says. "But the accusation that the regime is purposefully trying to make the Iraqi people suffer doesn't hold."

"Governments are changing their attitudes to the Iraq file," says Von Sponeck. "The big question is: Can that pressure translate into swaying the very inflexible positions of the Americans and British? This has become a moral issue."

Iraq should be proof that sanctions just don't work, he adds. Apartheid-era sanctions on South Africa are often a case that is raised by supporters of sanctions as a case that worked, but Von Sponeck was head of the UN in neighboring Botswana at the time, and disagrees.

"People forget that the sanctions period was short, and the first victims were the blacks in South Africa," he says.

Pope John Paul II helped set the tone during his 1998 visit to Cuba - where four decades of sanctions have failed to unseat Mr. Castro - saying that sanctions are "always deplorable, because they hurt the most needy."

The transformation in Von Sponeck's thinking is an apt mirror of that taking place elsewhere. When he first arrived in Iraq, "the word 'sanctions' was like a cow in India - it was very holy: don't talk about it," he says. But his "mental adjustment" was prompted by the situation in Iraqi schools, where children were learning in such isolation - printed materials have been forbidden under sanctions - that they can never be "responsible citizens."

"The biggest lesson of the last 10 years," Hufbauer says, is that "sometimes sanctions are successful when you have modest goals and an open regime. But sanctions are a fair-weather tool of diplomacy. You can't expect them to do the heavy lifting, just as you wouldn't send in a crew with shovels to dig out a major road through rock."